/**
 * ***************************************************************************** Copyright (c) 2000,
 * 2008 IBM Corporation and others. All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * <p>Contributors: IBM Corporation - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.ltk.core.refactoring;

import org.eclipse.ltk.core.refactoring.history.IRefactoringExecutionListener;

/**
 * Listener to monitor state changes of an {@link IUndoManager}.
 *
 * <p>Clients may implement this interface to listen to undo manger changes.
 *
 * <p>As of 3.2 clients which need to examine refactorings which have been performed, undone or
 * redone should use {@link IRefactoringExecutionListener} for enhanced functionality.
 *
 * @since 3.0
 */
public interface IUndoManagerListener {

  /**
   * This method is called by the undo manager if the undo stack has changed (for example a undo
   * object got added or the undo stack got flushed).
   *
   * @param manager the manager this listener is registered to
   */
  public void undoStackChanged(IUndoManager manager);

  /**
   * This method is called by the undo manager if the redo stack has changed (for example a redo
   * object got added or the redo stack got flushed).
   *
   * @param manager the manager this listener is registered to
   */
  public void redoStackChanged(IUndoManager manager);

  /**
   * This method gets called by the undo manager if a change gets executed in the context of the
   * undo manager.
   *
   * @param manager the manager this listener is registered to
   * @param change the change to be executed
   */
  public void aboutToPerformChange(IUndoManager manager, Change change);

  /**
   * This method gets called by the undo manager when a change has been executed in the context of
   * the undo manager.
   *
   * @param manager the manager this listener is registered to
   * @param change the change that has been executed
   */
  public void changePerformed(IUndoManager manager, Change change);
}
